Add erlang to pycco literal programming

pycco.diff

diff --git a/pycco b/pycco
index aaabb7b..bbe1b04 100755
--- a/pycco
+++ b/pycco
@@ -163,6 +163,7 @@ languages = {
     ".py":     { "name": "python",        "symbol": "#" },
     ".scm":    { "name": "scheme",        "symbol": ";;" },
     ".lua":    { "name": "lua",           "symbol": "--" },
+    ".erl":    { "name": "erlang",           "symbol": "%%" },
 }
 
 # Build out the appropriate matchers and delimiters for each language.